A radio transmitter includes a unit which generates a first instruction to
instruct the transmission of a first transmission signal, a unit which
generates the first transmission signal based on the first instruction, a
unit which generates a second instruction to instruct the transmission of
a second transmission signal to be selectively multiplied by an
orthogonal code, a unit which generates the second transmission signal
based on the second instruction, unit which transmits the first and the
second transmission signals, a unit which predicts a collision of the
first and second transmission signals, and a unit which stops the first
transmission signal while the collision is predicted in a case where the
second transmission signal is multiplied by the orthogonal code and which
stops the second transmission signal while the collision is predicted in
a case where the second transmission signal is not multiplied by the
orthogonal code.